1. Field of the Invention
The present invention relates to an overtube and an endoscope system for performing treatment such as submucosal dissection using a manipulator apparatus under observation by an endoscope.
2. Description of the Related Art
In recent years, procedures have been performed such as endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) of providing a plurality of treatment instrument channels in an insertion portion of an endoscope, introducing treatment instruments such as a grasping device and an IT knife into a body through the respective treatment instrument channels to resect a lesion in mucosal tissue in the body. Clinicians who preform the procedures need good skills.
In recent years, various manipulators including an active joint have been invented for a treatment instrument to be inserted into a treatment instrument channel of an endoscope to improve operability of an operator.
For example, Japanese Patent Application Laid-Open Publication No. 2004-89591 (hereinafter referred to as Document 1) discloses a medical manipulator system including a plurality of manipulators. The medical manipulator system includes the plurality of manipulators having treatment tools in distal ends. In the medical manipulator system, single joint manipulators 11, 12 and 13 each including one joint protrude from holes provided in an insertion cylinder 15 as shown in FIG. 2 in Document 1. The manipulator is not limited to the single joint manipulator, but may be a multijoint manipulator (also referred to as a multi-degree-of-freedom manipulator) including a plurality of joints.
An example of the multijoint manipulator is a multijoint knife 100 in FIG. 1. The knife 100 includes, for example, a prismatic drive joint 102, a pitch drive joint 103, a yaw drive joint 104, a pitch drive joint 103, and a yaw drive joint 104 in order as active joints on a distal end side of a treatment instrument insertion portion 101, and includes a knife arm 105 on a distal end side of the yaw drive joint 104 at a most distal end.
FIGS. 4(a) and (b) in Japanese Patent Application Laid-Open Publication No. 2004-154877 (hereinafter referred to as Document 2) show a multijoint manipulator including consecutive yaw drive joints and consecutive pitch drive joints. Further, FIG. 3 in Japanese Patent Application Laid-Open Publication No. 8-224244 (hereinafter referred to as Document 3) shows a multijoint manipulator including a plurality of rotary joints only as pitch drive joints.
The multijoint manipulator is operated by solving an inverse problem or a forward problem. An operation by solving a forward problem is an operation in a so-called master/slave mode, and an operator operates a master portion and thus a slave portion reproduces movement of the master portion.
On the other hand, in an operation by solving an inverse problem, an operator provides target values of a position and an attitude of a distal end of, for example, a knife arm. Then, a CPU solves a joint angle path of each joint for the target values, then operates a drive actuator (not shown), pulls and releases an operation wire (not shown) by a predetermined amount to rotate each joint clockwise or counterclockwise to change a joint angle. Then, the position and the attitude of the distal end of the knife arm are set to the target values.
In the case of solving the inverse problem and setting the position and the attitude of the distal end of the knife arm to the target values in a body as described above, the operator needs to previously grasp a situation around the knife arm. If the operator insufficiently grasps the situation, an operation of the active joint may bring the knife arm or the joint into contact with a body wall or the like. In the master/slave mode, for example, the operator operates a master portion to move the knife arm or the like while observing an endoscope image. Thus, the operation of the knife arm can be stopped by the operator stopping the operation of the master portion, thereby preventing the disadvantage described above.
However, in Document 1, when the plurality of multijoint manipulators are protruded from the holes in the insertion cylinder 15 to perform treatment, a distance between an endoscope 10 provided in the hole in the insertion cylinder 15 and an area to be treated increases with increasing number of joints of the manipulators. This reduces a size ratio of an image of the area to be treated displayed on a screen of a display apparatus with respect to a size of the screen. To eliminate the disadvantage, if the endoscope 10 is protruded from the hole in the insertion cylinder 15 and brought close to an observation area, joints or the like on a proximal end side of a distal end surface of the endoscope are not displayed on the screen.